Spiral belt joint

ABSTRACT

A joint connecting adjacent spirally wound coils of woven wire where two spirally wound wire coils are disposed in substantially parallel position and have intermeshing convolutions. A rod having alternate flat and round sections longitudinally along its length extends through the intermeshing convolutions with the convolutions engaging the round sections of the rod.

United States Patent 1191 Curran et al. 14 1 May 8, 1973 [54] SPIRAL BELT JOINT 2,619,306 11 1952 Van Lake ..198 193 1 1 11:12:: 2112:: 11:12:;;;.-.::;-.-.:;;.-.-.: "1. 32132 Fredericks, Chesterland; James 3,276,570 10/1966 111111. eta]. 1 ..245/6 D. Marshall, Mentor, all of Ohio 3,376,002 4/1968 Andrews et a] ..245/6 Assigneer Tyler Incorporated, Mentor, FOREIGN PATENTS OR APPLICATIONS 1,051,726 1 2/1959 Germany [22] Filed: Apr. 30, 1971 PrimaryExaminer-Richard J. Herbst [2H Appl' 139347 Attorney-Fay, Sharpe and Mulholland Related US. Application Data 57 ABSTRACT [63] Continuation of Ser. No. 8l7,962, April 21, 1969,

abandoned 1 A oint connecting ad acent splrally wot 1nd colls of woven wlre where two spirally wound w1re coils are disposed in substantially parallel position and have in- [gi] ..245g56,sl9$131g(3) termeshing convolutions A rod having alternate flat g and round Sections longitudinally along its length Fle d of Search l 245/6, tends through the intermeshing con olutions the convolutions engaging the round sections of the rod. References Cited 15 Claims, 10 Drawing Figures PATENTEDMY 81% 3,731,894 I SHEET 1'01 3 FIG. 2

FIG. 4A

INVENTORS JOHN D. CURRAN BY ZYGMUNT s. FREDERICKS JAMES 0. MARSHALL ATTORNEYS SPIRAL BELT JOINT This application is a continuation of Ser. No. 817,962 filed Apr. 21, 1969, now abandoned.

BACKGROUND OF THE INVENTION tional structure includes spirally wound coils lying in l substantially parallel relationship with the coils intermeshing and a reinforcing rod extending through the intermeshing convolutions.

In some instances, all the spirals are intermeshed and connected to each other only through the rod and together they make up a woven wire fabric called a balanced spiral weave. In the balanced weave fabric, the intermeshed coils of adjacent spirals alternatingly loop around the rod along its length but do not engage each other. The only connection between the spirals is the rod itself with the seats for the loops alternating from one side of the rod to the other and being longitudinally spaced apart along its length.

Similar conventional structure may include a rod reinforced weave in which the intermeshed spirals are also interconnected, that is, loops of adjacent spirals overlap and the seats are contiguous on opposite sides of the rod. The purpose of the connecting bar is to reinforce the weave, hence the name rod reinforced.

One problem which is particularly troublesome in the industry is the unpredictable width contraction and the elongation of the belt when it is placed in tension.

The combined elongation and width contraction tends to place a greater tension on the edge portions of the belt than on the remainder, with resulting unsymmetrical loading. This is particularly undesirable because it is conventional to weld the ends, or at least one end of the rods to one of the spiral coils. Thus, the greater tension on the edge portions of the belt will tend to break or accentuate the wear on the weld.

Unsymmetrical loading causes the belt to track to one side or the other. This undesirable side tracking is further magnified when unsymmetrically arrayed material is placed on the belt. In addition to causing excessive edge tension, uneven loading also urges the convolutions of the spirals to slip to one side or the other on the rod and they tend to bunch at the point of greatest tension, thereby unevenly loading the rods. The stress concentrations which result often cause excessive wear on one part of the rod and failure occurs in a short period of time. Shifting of some of the convolutions of the coils also adds an additional tension on the edge weld of the belt with resulting accelerated wear.

BRIEF DESCRIPTION OF THE INVENTION An analysis of the problems in the industry has shown the need for some structure which will maintain the uniform spacing of the convolutions along the longitudinal length of the rod when the belt is placed in tension to thereby relieve the stress concentrations on the rod per se and to prevent excessive edge tension. In addition, the same problems show the need for a stiffer rod without increased weight.

This is achieved by this invention which provides a rod having alternate round and flat sections along its length. The loops of the coils engage the round sections of the rod and the adjacent flat sections provide shoulder means for retaining the loops in properly spaced relationship. This structure helps prevent any substantial narrowing of the belt and precludes stress concentrations on the rod when the belt is loaded. At the same time the flattened sections tend to stiffen the rod and strengthen the belt in a plane substantially parallel with the surface of the flat sections. As a result, when the flat sections of the rod are aligned with the plane of the belt, the belt itself has a greater strength in tension. When the flat sections of the rod are aligned perpendicular to the plane of the belt, the camber strength of the belt is increased.

It is an object of this invention to provide an improved joint between adjacent spirally wound coils of a woven wire belt by providing alternate flat and round sections along the length of the connecting rod where the convolutions of the adjacent coils engage the round sections of the rod.

It is a further object of this invention to provide an improved joint between adjacent spirally wound coils of a woven wire belt whereby the inner surface of the loops substantially conforms to the surface of the connecting rod to provide maximum surface contact.

It is a further object of this invention to provide an endless conveyor belt which includes a plurality of intermeshing spirally wound coils connected by rods where the rods have alternate round and flat sections throughout their length.

It is a further object of this invention to provide a connector rod for coils of a woven wire belt which is stiffer than a conventional rod and includes means to maintain the original spacing of the convolutions of the coils.

It is a further object of this invention to provide a connector rod for coils of a woven wire belt which includes seats spaced along the length of the rod which define a smooth curve in two orthogonal planes.

It is a further object of this invention to provide an endless conveyor belt comprising a plurality of intermeshing spirally wound coils connected by rods and where at least some of the rods include alternate flat and round sections throughout their length and the convolutions of the spirally wound coils engage the round sections of the rods.

These and other objects of the invention will become obvious from the following detailed! description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary plan view of a woven wire belt of a balanced spiral weave incorporating the improved connecting rod of the invention;

FIG. 2 is a sectional view taken along line 2 2 of FIG.

FIG. 3 is a fragmentary plan view of a woven wire belt of a rod reinforced weave incorporating a modification of the improved rod of this invention;

FIG. 4 is a plan view of the improved rod of this invention;

FIG. 4a is an elevational view of the improved rod of FIG. 4;

FIG. 5 is a plan view of a modification of the improved rod of this invention;

FIG. 5a is an elevational view of the improved rod of FIG. 5;

FIG. 6 is a fragmentary plan view of a woven wire belt of a balanced weave fabric and employing the improved rod of this invention as every other rod;

FIG. 7 is a graph of the deflection in inches versus load in ounces for various shapes of connector rods for woven wire belts; and

FIG. 8 is a graph of load in pounds versus elongation in inches for woven wire belts using various shapes of connector rods.

PREFERRED EMBODIMENT Referring to FIG. 1, a woven wire conveyor belt 10 includes a plurality of adjacent intermeshed spirally wound wire coils 12 connected by a plurality of rods 14. The particular weave illustrated in FIG. 1 is of a balanced spiral fabric. Each coil 12 includes a plurality of convolutions 16 having two end loops 18 joined by side pieces 20. The sidepieces 20 may be slightly curved, as shown particularly in FIG. 2.

Each rod 14, best illustrated in FIGS. 4 and 4a, includes alternate flat 22 and round 24 sections.

The end loops 18 of each of the convolutions l6 swings around a round section 24 of one of the rods 14. When the woven wire conveyor belt is placed in operation and subjected to load, the loops 18 are placed in tension and their inner surface tends to conform to the configuration of the seat or round section 24 provided on the rod. It is desirable to provide maximize surface contact between the seat 24 and the loop 18 to minimize wear at any isolated point. Thus, the rod of this invention provides a smooth curve in two orthogonal planes, one parallel to the axis of the rod and the other perpendicular to the rod. The seat 24 is substantially circular or oval in cross section (see FIG. 2) and between the shoulders 26 of the plastically deformed sections 22, the seats define smooth inwardly dipping curves (see FIG. 4).

A conventional woven wire belt tends to narrow in width when it is placed in tension. Also, without the particular structure of the rod of this invention, any unsymmetrical loading of the belt urges the convolutions 16 to move or slide. Thus, when a large load is applied to a belt having straight round rods, the loops l8 tend to bunch. This places a great shear load on one section of the rod and inherently the stress concentration weakens the joint overall. This invention has provided seats 24 uniformly spaced along the rod between the plastically deformed flat sections 22 to maintain the convolutions 16 in equally spaced position.

Each flat section 22 is formed by plastic deformation of a round rod to provide two relatively flat surfaces. The deformed flat section 22 inherently form rounded shoulders 26 in a smooth transition from the seats 24 and these shoulders tend to bias the loops 18 toward the centers of the seats 24, thus preventing side slippage of the loops 18 relative to the rod 14. Plastic deformation is superior to cutting because of the inherent stress concentrations which result from the sharp corners of a cut.

The unique seat feature of the rods tends to maintain the original width of the woven wire belt, reduce stress concentration on the edges, and prevent bunching of the loops 18 which reduces shear stress concentrations along the length of the rod.

Observing FIGS. 3, 5 and 5a, a woven wire belt 31 is shown with the spiral coils 32 interlocked at 34 in a rod reinforced weave. Each rod 38 is shown to have alternate flat 40 and round 42 sections in the same manner as the rods 14 of FIG; 4. The rods of FIG. 5 are distinct from the rods of FIG. 4 in that the flat sections 40 of the rods 38 are greater in length than the round sections 42, whereas the flat and round sections of the rod 14 are of substantially the same longitudinal length although the round sections could be made longer than i the flat sections if desired. Whether a rod such as rod 14 or rod 38 is used does not depend upon the particular kind of weave used in the belt, but instead is only related to the pitch of the coils. That is, the only concern is to have one round section 24 for engagement by each loop 18. Thus, a balanced spiral weave could be used with the rod 38 or a rod reinforced weave could be used with rod 14. The particular weaves shown are by way of illustration only.

FIG. 6 illustrates a feature of the invention wherein half of the connecting rods are a crimped annular rod 48 and the other half have the alternate flat and round sections illustrated in FIG. 4.

While it is anticipated that the rods of this invention may be used at every joint, it is important to note that the ability of the rods to keep the convolutions l6 equally spaced across the width of the belt is so effective that some conventional rods may be used without substantial detrimental effect. In some instances the rods 14 of 38 of this invention may be needed at only every fifth joint while still maintaining the proper spacing of the convolutions 16. For other conveying operations such as illustrated in FIG. 6, it is desirable to have the improved connecting rod at only every second joint.

It should be noted that in FIGS. 1, 3 and 6, the rods of this invention are illustrated as having the flat sections parallel or substantially parallel with the surface of the woven wire belt. When they are aligned in this manner, the flat sections tend to act as beams to some extent which stiffens the rods in a plane parallel with the plane of the belt. However, the particular orientation of the rods is only illustrative. When particularly heavy pieces of equipment are to be conveyed on the belt, it has been found useful to orient the flat sections perpendicular to the plane of the belt and thereby (1) provide greater camber strength and (2) minimize unsymmetrical loading across the belt width.

To determine the effectiveness of the rods of this invention in minimizing belt elongation and width contraction, tests were conducted comparing it with a conventional round rod. The rods were tested with the load normal to both the plan view and the side views illustrated in FIGS. 4, 4a, 5 and 5a. The rods were also tested in the annealed and unannealed condition in order to evaluate the contribution of both cold working and change in geometry to the increased stiffness.

FIG. 7 shows the results of tests for stiffness of the rods per se. In the test apparatus, the ends of the rods were suspended and a load was attached at the center. Deflection in inches was measured for each of the plurality of shapes of rod as indicated by the legend in FIG. 7, both in the annealed and unannealed conditions. The test results graphically illustrate the increased stiffness of the rods of this invention when stressed parallel with the flat sections.

width was placed in tension. The test results graphically illustrated in FIG. 8 show the reduced elongation of a belt when rods of this invention are used as compared to the round or crimped rods currently used in the industry. The V-shaped sections of the curves indicate the loads at which the welds at the edges of the belt were broken.

For ease of description the principles of the invention have been set forth in connection with but a few illustrated embodiments. It is not intended that the illustrated embodiments nor the terminology employed in describing them be limiting inasmuch as variations in these may be made by one having ordinary skill in the art without departing from the scope and spirit of the invention. Rather, it is intended that any restrictions on the invention be limited to the spirit and scope of the appended claims.

We claim: 7

1. A joint connecting adjacent spirally wound coils of a woven wire belt comprising:

two spirally wound wire coils disposed in substantially parallel position,

each coil including a plurality of convolutions and with the convolutions of the parallel coils intermeshing,

a connecting rod extending through the intermeshing convolutions,

the rod comprising alternate flat and round sections longitudinally along its length,

the convolutions engaging the round sections of the rod,

said flat sections including means for (l) stiffening the rod in a plane parallel to said flats and (2) maintaining uniform spacing of the convolutions along the rod.

2. The joint of claim 1 wherein the inner surface of the convolutions substantially conform to the curvature of the round sections of the rod to provide maximum surface contact.

3. The joint of claim 1 wherein the flat sections of the rod are substantially parallel to the surface of the belt. a

4. The joint of claim 1 wherein the flat sections of the rod are substantially perpendicular to the plane of the belt.

5. The joint of claim 1 wherein the longitudinal length of the flat sections along the rod are substantially the same as that of the round sections.

6. The joint of claim 1 wherein the longitudinal length of the flat sections of the rod is greater than that of the round sections.

'7. The joint of claim 1 wherein the surface of the round sections of the rod merge with the flat sections in a smooth curve.

8. The joint of claim 7 wherein the smooth curves define seats to receive the coil convolutions.

9. The joint of claim 1 wherein the adjacent coils are interlocking.

10. The joint of claim 1 wherein the convolutions of adjacent coils are uniformly spaced apart along the length of the rod.

11. An endless conveyor belt comprising a plurality of intermeshing spirally wound wire coils connected by rods,

the rods extending substantially parallel with the plane of the belt and at least some of the rods including alternate flat and round sections along their length,

said flat sections including means for (l) stiffening the rod in a plane parallel to said flats and (2) maintaining uniform spacing of the spaced wire portions forming said coils along the rod.

12. The endless belt of claim 111 wherein the rods having alternate flat and round sections are uniformly periodically spaced along the belt and comprise from one-fifth to one-half of the total number of rods.

13. The endless belt of claim 11 wherein the flat sections of the rods are substantially parallel with the plane of the belt.

14. The endless belt of claim 11 wherein at least some of the rods include flat sections which are substantially perpendicular to the plane of the belt.

15. A joint connecting adjacent wound coils of a woven wire belt comprising:

two coils intermeshing and with each including a plurality of loops having spaced upper and lower elongated flight portions respectively defining upper and lower portions of the belt and curved bight portions extending between said flight portions at the opposite ends of each loop,

a substantially round connecting rod extending through the intermeshing loops to join the coils together,

the rod including a plurality of spaced, inwardly impressed indentations along its length, said indentations being located only in the surface regions of the rod which face toward said flight portions of the loops through which the rod extends, said indentations defining flat lengths of said rod and said flat lengths being separated by axially spaced round lengths,

said flat sections including means for l) stiffening the rod in a plane parallel to said flats and (2) maintaining uniform spacing of the convolutions along the rod. 

1. A joint connecting adjacent spirally wound coils of a woven wire belt comprising: two spirally wound wire coils disposed in substantially parallel position, each coil including a plurality of convolutions and with the convolutions of the parallel coils intermeshing, a connecting rod extending through the intermeshing convolutions, the rod comprising alternate flat and round sections longitudinally along its length, the convolutions engaging the round sections of the rod, said flat sections including means for (1) stiffening the rod in a plane parallel to said flats and (2) maintaining uniform spacing of the convolutions along the rod.
 2. The joint of claim 1 wherein the inner surface of the convolutions substantIally conform to the curvature of the round sections of the rod to provide maximum surface contact.
 3. The joint of claim 1 wherein the flat sections of the rod are substantially parallel to the surface of the belt.
 4. The joint of claim 1 wherein the flat sections of the rod are substantially perpendicular to the plane of the belt.
 5. The joint of claim 1 wherein the longitudinal length of the flat sections along the rod are substantially the same as that of the round sections.
 6. The joint of claim 1 wherein the longitudinal length of the flat sections of the rod is greater than that of the round sections.
 7. The joint of claim 1 wherein the surface of the round sections of the rod merge with the flat sections in a smooth curve.
 8. The joint of claim 7 wherein the smooth curves define seats to receive the coil convolutions.
 9. The joint of claim 1 wherein the adjacent coils are interlocking.
 10. The joint of claim 1 wherein the convolutions of adjacent coils are uniformly spaced apart along the length of the rod.
 11. An endless conveyor belt comprising a plurality of intermeshing spirally wound wire coils connected by rods, the rods extending substantially parallel with the plane of the belt and at least some of the rods including alternate flat and round sections along their length, said flat sections including means for (1) stiffening the rod in a plane parallel to said flats and (2) maintaining uniform spacing of the spaced wire portions forming said coils along the rod.
 12. The endless belt of claim 11 wherein the rods having alternate flat and round sections are uniformly periodically spaced along the belt and comprise from one-fifth to one-half of the total number of rods.
 13. The endless belt of claim 11 wherein the flat sections of the rods are substantially parallel with the plane of the belt.
 14. The endless belt of claim 11 wherein at least some of the rods include flat sections which are substantially perpendicular to the plane of the belt.
 15. A joint connecting adjacent wound coils of a woven wire belt comprising: two coils intermeshing and with each including a plurality of loops having spaced upper and lower elongated flight portions respectively defining upper and lower portions of the belt and curved bight portions extending between said flight portions at the opposite ends of each loop, a substantially round connecting rod extending through the intermeshing loops to join the coils together, the rod including a plurality of spaced, inwardly impressed indentations along its length, said indentations being located only in the surface regions of the rod which face toward said flight portions of the loops through which the rod extends, said indentations defining flat lengths of said rod and said flat lengths being separated by axially spaced round lengths, said flat sections including means for (1) stiffening the rod in a plane parallel to said flats and (2) maintaining uniform spacing of the convolutions along the rod. 